Two of the women allegedly abducted by Ariel Castro 10 years ago in Cleveland are lucky to be alive after one of them suffered five miscarriages because Castro allegedly punched her in the gut and the other was forced to give birth in a basement with no medical help, obstetricians said today.

Michelle Knight, 32, was impregnated five times by Castro, but he aborted the fetuses by punching her repeatedly in the abdomen, according to a police report obtained by ABC News affiliate WEWS-TV.

"To be quite honest, I've been doing obstetrics 17 years and spent 10 as a midwife, and I've never actually heard of somebody being beaten so severely that it would cause a miscarriage," said certified nurse and midwife Pam Hetrick, who works at University Hospitals Case Medical Center in Cleveland. She did not treat Knight.

Knight probably miscarried when she was at least 12 weeks pregnant because it's unlikely that blunt trauma would cause a miscarriage before that, said Dr. Taraneh Shirazian, an OB/GYN at Mount Sinai Medical Center who directs its global health program. This is because the uterus is small enough to be protected by the pelvis during the first trimester, but by the second trimester, Knight's belly would have been exposed. Then, when Castro allegedly punched her, she would have had a placental abruption, cutting off the baby's blood supply.

"It's still pretty unusual," Shirazian said. "In order for that to happen, I would assume it was pretty brutal blunt trauma."

Complications Knight could have faced included hemorrhaging and infection, Hetrick said.

The fetuses also could have died inside Knight without causing her to go into labor, putting her at risk for even more complications, such as a fatal blood clotting disorder, Hetrick said. If Knight's cervix was repeatedly forced open to remove the fetuses, she could face problems in future pregnancies.

"It's unusual to not be breathing at delivery for a full term baby," Shirazian said. "I think that's actually a pretty remarkable feat if she never had any resuscitation training."

It's not clear whether Berry delivered prematurely.

Hetrick said Berry could have faced complications during birth including infection and bleeding, but she and the baby could have also died if her labor stopped progressing. She said that although Ohio has seen a rise in home births, those are usually attended by a midwife or someone else with birth training. If labor stops progressing, or another complication occurs, they know what to do.

"Typically women who choose home birth, if they get into trouble, they will come and get medical care," Hetrick said. "It doesn't sound like he would have taken her to medical care if there would have been an obstetric complication. She could have died."

Dr. Kimberly Fortner, an OBGYN at Vanderbilt University Medical Center, said that Berry is also lucky that her red blood cells didn't lack a certain protein, called the Rh factor, which could have caused her immune system to attack the baby's blood if it didn't match her blood. About 20 percent of Caucasian women lack this protein, she said, but this is easily fixed with an injection of a drug called Rh immunoglobulin.

But Berry wouldn't have had that injection.

"We know that women can give birth without intervention," Hetrick said. "Amanda didn't have that choice. Amanda was left in the basement in the kiddie pool to give birth by herself without any support, and it had to be extremely terrifying."